Electronic band structure modulated by local surface strain in the (111) facet of the < 112 > silicon nanowires

Based on the models built with our cyclic replacement method we introduced local strain into the (111) facet of the Si < 112 > nanowires. With ab initio approach, it is found that the electronic band structures of the nanowires are modulated efficiently by the surface strains: the indirect band gap declines by strong surface compression, while it always decreases and impressively changes to a direct band gap with surface tension. Moreover, the local deformations result in spatial separation of the valence band minimum to the compressed surface and the conduction band minimum to the tensed surface. (C) 2015 Elsevier Ltd. All rights reserved.